A handheld steamer typically comprises a small water tank, a low flow pump and a lower power steam generation unit in the same handle. In most handheld steamers, the mechanism for steam generation is flash boiling or flow-through heating, depending on the steam rate, wherein steam is produced on demand by pumping—i.e. by dosing water over a hot surface. Steam vents nearby then let the steam out onto the garment. Due to constraints of size and weight for such a product, such steamers tend to produce only limited amount of steam.
For instantaneous steam generation in handheld steamers, large steam rates are harder to achieve in a limited space because this requires managing large volumes of water and energy extraction instantly within the aforementioned limited space. Flow-through heating is often used to increase heat extraction surface for water flowing through, which makes it possible to get higher steam rates, but still not as high as boilers or heating bowl. However, a higher steam rate leads to more scale whenever hard natural water is involved, and the steam rate optimised “labyrinth” designs of flow-through heaters may often end up getting clogged with scale rather quickly. Since the inside of such flow-through heaters cannot be accessed, the clogging cannot be removed/cleaned, leading to the product becoming non-functional.
US 2005/169614 discloses equipment for producing high-pressure saturated steam. The equipment includes a water tank, a pump, a check valve, an atomizing nozzle, a hollow heat chamber and a steam outlet. The pump is connected between water tank and the check valve. The check valve is connected with the heat chamber via the atomizing nozzle. The atomizing nozzle extends into the hollow heat chamber to spray water into the chamber.